#!/usr/bin/env python
#-*- coding:utf-8 -*-
 
import threading
from time import sleep,ctime
 
loops = [4,2]
 
def loop(nloop,nsec):
    print('start loop %s at %s ' % (nloop,ctime()))
    sleep(nsec)
    print('loop %s done at %s' % (nloop,ctime()))
 
def main():
    print('starting at %s' % ctime())
    threads = []
    nloops = range(len(loops))
    for i in nloops:
        t = threading.Thread(target=loop,args=(i,nloops[i]))
        threads.append(t)
    for i in nloops:
        threads[i].start()
    for i in nloops:
        threads[i].join()
    print('all down at %s' % ctime())
 
if __name__=='__main__':
    main()